Delivery of fuel to an engine may be compromised due to cavitation in a fuel pump supplying fuel to the engine. Cavitation may occur by the formation of vapor bubbles in the fuel pump. Further, cavitation may be exacerbated by using fuels with higher volatility (e.g., a higher Reid Vapor Pressure), as well as due to higher ambient temperatures and/or lower atmospheric pressures. Engine operation may be adversely affected by cavitation and the engine may experience issues such as engine hesitation, an unexpected loss of torque, and potential engine stall. As such, hybrid vehicles and non-hybrid vehicles that are equipped with start-stop systems may experience frequent engine starts. A loss of torque following engine start in these vehicles may severely impact engine operation, drivability, and operator experience.
The inventors herein have recognized the above issues and identified approaches to at least partly address the issues. In one example approach, a method for an engine in a vehicle comprises following an engine start, adjusting engine operation or fuel pump operation responsive to detection of cavitation in a fuel pump, the detection of cavitation based on ambient conditions and a measured engine torque being lower than a desired engine torque after a first pre-determined duration.
For example, fuel may be supplied to an engine in a vehicle by a fuel system including a fuel pump and a fuel tank. The vehicle may be a hybrid vehicle or a vehicle including a start-stop system. Further, the fuel in the fuel tank may have a higher volatility and an ambient temperature may be sufficiently high to enhance vaporization of fuel in the tank. If, upon an engine start and following a first pre-determined duration, a measured engine torque is determined to be lower than a desired engine torque, a likelihood of cavitation in the fuel pump may be established. In response to the cavitation, various remedying actions may be undertaken including adjusting engine operation and/or modifying fuel pump operation. For example, modifying fuel pump operation may include one or more of activating and deactivating the fuel pump repeatedly for the second pre-determined duration, deactivating the fuel pump for a third pre-determined duration, and operating the fuel pump at a higher speed for a fourth pre-determined duration. Further, adjusting the engine operation may include commanding an engine restart and/or delaying engine start until the fuel pump is operated at a higher speed for the fourth pre-determined duration.
In this way, adverse effects of cavitation on engine operation may be alleviated. By identifying that a loss of engine torque following an engine start is due to cavitation, various actions specific to mitigating cavitation may be applied. Further, a likelihood of engine stalls may be reduced. Overall, engine performance may be enhanced and drivability may be improved.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.